TABLE OF CONTENTS

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Appendix BRestore Bald Eagles to the Channel Islands

B.1Goals and Nexus to Injury

B.2Background

B.2.1Historical Presence of Bald Eagles on the Channel Islands

B.2.2Ecological Role of Bald Eagles on the Channel Islands

B.2.3Santa Catalina Island Bald Eagle Program

B.2.4Northern Channel Islands Bald Eagle Feasibility Study

B.3Complete the NCI Bald Eagle Feasibility Study Before Deciding on Further Restoration Actions

B.3.1Project Description and Methods

B.3.2Environmental Benefits and Impacts

B.3.3Likelihood of Success/Feasibility

B.3.4Performance Criteria and Monitoring

B.3.5Evaluation

B.3.6Budget

B.4Complete the NCI Bald Eagle Feasibility Study; Regardless of its Outcome, Continue Funding Santa Catalina Island Bald Eagle Program

B.4.1Project Description and Methods

B.4.2Environmental Benefits and Impacts

B.4.3Likelihood of Success/Feasibility

B.4.4Performance Criteria and Monitoring

B.4.5Evaluation

B.4.6Budget

Figures

B-1.Levels of DDE in Santa Catalina bald eagle failed-to-hatch eggs from 1989–2004.

B-2.Levels of PCBs in Santa Catalina bald eagle failed-to-hatch eggs from 1989–2004.

I:\26814586\Final\B final 10-24-05.docMSRP Final RP/EIS/EIR October 2005 1

Appendix B

Restore Bald Eagles to the Channel Islands

Appendix B
Restore Bald Eagles to the Channel Islands

Appendix BTier 2 Evaluation of Restoring Bald Eagles to the Channel Islands

Bald eagle restoration throughout the Channel Islands presents a special situation because bald eagles introduced to and currently nesting on Santa Catalina Island continue to exhibit reproductive injuries caused by ongoing exposures to DDTs and PCBs. Also, bald eagles historically inhabited most of the Channel Islands, and we do not yet know if they would have greater success reproducing on islands other than Santa Catalina Island (none of the Catalina Island bald eagles has dispersed to and established territories on any of the other Channel Islands). Thus, selecting restoration actions requires consideration of interrelated factors and depends ultimately on the outcome of the ongoing Feasibility Study for Reestablishment of Bald Eagles on the Northern Channel Islands (NCI), California (MSRP 2002). (This ongoing study is referred to as the “NCI Bald Eagle Feasibility Study” throughout this appendix.) Sections B.3 and B.4 describe and evaluate the two contrasting options for bald eagle restoration that this plan addresses.

B.1Goals and Nexus to Injury

The bald eagle is a priority resource for restoration that continues to demonstrate injury from the contaminants of the Montrose case. The overall goal for this resource is for the Natural Resource Trustees for the Montrose case (Trustees) to restore self-sustaining bald eagles to the Channel Islands. Bald eagles historically nested throughout the Channel Islands prior to releases of DDTs and PCBs, but by the early 1960s had disappeared from the area (Kiff 1980). In 1980, a multiagency program reintroduced the birds to Santa Catalina Island but their breeding continues to be impaired by these contaminants. Due to the continued presence of DDTs and PCBs in their environment, it is not yet known to what extent the bald eagle restoration goal is attainable in the near term.

B.2Background

Bald eagles were a resident breeding species on all of the California Channel Islands from before the turn of the century until at least the 1930s (Willett 1933, Kiff 1980). Ornithologists and egg collectors reported bald eagles to be common on the Northern Channel Islands between the late 1800s through the 1930s. From the 1800s to 1950, bald eagle nesting areas were reported from a minimum of 35 different locations on the islands, making the Channel Islands a stronghold for this species in Southern California (Kiff 2000). However, due to the lack of systematic surveys, this number is likely an underestimate (Kiff 2000). The last confirmed nesting of an eagle on the Channel Islands was in 1949 on Anacapa Island (Kiff 1980).

Little published information is available regarding the status of bald eagles on the Channel Islands after the 1940s, but a few adult birds continued to be observed on some of the islands into the late 1950s and 1960s. Santa Catalina Island residents remember seeing eagles up until the mid to late 1950s (Kiff 1980, Garcelon 1988). By the early 1960s, bald eagles had disappeared from all of the Channel Islands (Kiff 1980). The timing of the decline of bald eagles on the Channel Islands coincided closely with the extirpation of peregrine falcons and bald eagles from other portions of their North American range as a result of the eggshell thinning effects of DDE (Kiff 2000, Garcelon 1988). The reduction of bald eagle populations in many areas of the country has been correlated with high levels of organochlorine compounds and specifically with DDTs (Stickel et al. 1966, Krantz et al. 1970). Other factors contributing to the decline of bald eagles on the Channel Islands and Southern California included historical persecution by humans (egg collecting and shooting) and limited nesting opportunities on the mainland of Southern California due to development and recreation (Kiff 1980).

Raptor species, such as bald eagles and peregrine falcons, are particularly susceptible to these contaminants because they are high-trophic-level predators. Because DDTs and PCBs are slow to break down and are strongly attracted to fats, they bioaccumulate and become more concentrated in animals at higher levels in the food web. When feeding on food contaminated with DDE (a metabolite of DDT) and PCBs, animals at the top of the food web, like bald eagles and peregrine falcons, can accumulate harmful concentrations of these chemicals. DDE has been demonstrated to cause eggshell thinning and subsequent reproductive failure in many species of birds feeding in the marine ecosystem (Hickey and Anderson 1968, Risebrough et al. 1971, Gress et al. 1973). DDE in the diet of bald eagles has negatively affected the ability of the eagles to produce young (Wiemeyer et al. 1993). The continuing influence of this contaminant also accounted for the inability of bald eagles to recolonize the islands after other sources of mortality had ceased (Kiff 2000).

Bald eagles are currently listed as threatened under the Endangered Species Act, but have been proposed for delisting due to substantial recovery of the species on the mainland. In its Pacific Bald Eagle Recovery Plan, the U.S. Fish and Wildlife Service (USFWS) set recovery goals for bald eagles for specific zones in California. The Recovery Plan indicates that the most suitable habitat in Southern California is on the Channel Islands, especially Santa Cruz and Santa Catalina Islands (Jurek 2000, USFWS 1986). As outlined in the Recovery Plan, the recovery population goal is the minimum nucleus of nesting pairs that, if self-sustaining over the long term, will be capable of maintaining the genetic variability in the breeding population (USFWS 1986). This population goal is 6 nesting pairs for the Channel Islands zone and a minimum of 16 territories needed to provide secure habitat for the recovered population. Although Santa Catalina Island currently has 5 breeding pairs, they continue to suffer reproductive problems and are not considered self-sustaining (see Section B.2.3).

B.2.1Historical Presence of Bald Eagles on the Channel Islands

In a survey of historical records, Kiff (2000) showed the following maximum numbers of nesting bald eagles reported per island in a single year: Anacapa (3); San Miguel (3); Santa Cruz (5); Santa Rosa (3); Santa Barbara (1); Santa Catalina (4); San Clemente (3); and San Nicolas (1). Between 1875 and 1960, active eagle nests were reported from a minimum of 35 different sites on the Channel Islands.

Santa Cruz Island regularly supported a minimum of at least five pairs of bald eagles, which nested in niches and potholes on the sea cliffs (Kiff 1980). Known nesting areas on Santa Cruz Island included Pelican Bay, San Pedro Point, Blue Banks, Valley Anchorage, Chinese Harbor, Potato Harbor, and Middle Grounds. Anacapa Island had as many as three nesting pairs in some years. However, since collectors or ornithologists did not visit large portions of the Northern Channel Islands very often, if at all, the estimates of nesting pairs are likely an underestimate (Kiff 2000).

Grinnell (1897) visited San Clemente Island in 1897 and stated, “The Bald Eagle was seen rather commonly along the shores of the island.” The lack of ornithologist visits to the island after 1939 makes it impossible to speculate on the date of the bald eagle extirpation from the island. Few ornithologists visited San Nicolas Island historically, so the size of the eagle population is poorly known. However, there is no question that the species was formerly resident there (Kiff 2000). Finally, numerous ornithologists reported bald eagles to be common on Santa Catalina Island and present on Santa Barbara Island starting in the 1870s (Kiff 2000).

B.2.2Ecological Role of Bald Eagles on the Channel Islands

Bald eagles historically played a role in the ecology of the Channel Islands by serving as both a top carnivore and a scavenger. Bald eagles prey primarily on fish taken live from the ocean; however, they also feed on seabirds and the carcasses of animals that wash up on shore.

No other species plays the same ecological role as the bald eagle. In the absence of bald eagles on the Northern Channel Islands, golden eagles (not native to the Northern Channel Islands) have become established. Nesting adult bald eagles defend territories and would likely have excluded golden eagles from becoming established on the Northern Channel Islands (USFWS 2004). The golden eagle, a terrestrial predator, has had tremendous negative impacts on native island foxes in the Northern Channel Islands, a species that does not have evolutionary adaptations to avoid predation (Coonan 2001, Roemer 1999).

In addition to their role in the balance of natural systems, bald eagles were revered by Native American cultures historically occupying the Channel Islands and are still admired and valued by people for whom the bald eagle is both a striking bird and our American symbol.

B.2.3Santa Catalina Island Bald Eagle Program

In 1980, the USFWS and the Institute for Wildlife Studies, with the cooperation of the California Department of Fish and Game and the Catalina Island Conservancy, initiated a program to reintroduce bald eagles to Santa Catalina Island. Between 1980 and 1986, 33 eagles from wild nests were raised on three different artificial nest or hacking platforms on Santa Catalina Island (Garcelon 1988). The birds were released once they were able to fly (at around 12 weeks of age). Some of these birds matured and formed breeding pairs on the island. In 1987, the first bald eagle eggs were laid but soon broke. Subsequent contaminant analysis of egg remains revealed DDE levels sufficient to cause complete reproductive failure (Garcelon et al. 1989). From 1991 to 1993, the Institute for Wildlife Studies studied food habits of the released eagles and documented high levels of DDE in the tissues of certain prey items commonly consumed by these eagles (Garcelon 1997, Garcelon et al. 1997a, 1997b).

Since 1989, the reintroduced population has been maintained through manipulations of eggs and chicks at each nest site, and through hacking of additional birds. In the egg manipulation process, structurally deficient eggs laid by the birds affected by DDE are replaced with artificial eggs. The adult eagles continue to incubate the artificial eggs, while the real eggs are removed and artificially incubated at the Avian Conservation Center (ACC) at the San Francisco Zoo. Chicks that hatch from these removed eggs, or those produced by captive adults at the ACC or by wild birds, are then fostered back into the nests. In 2005, the Trustees funded the establishment of an incubation facility on Santa Catalina Island so that eggs and chicks would not need to be transported to and from the ACC at the San Francisco Zoo.

From 1980 to 2004, a total of 80 eggs were removed from nests on Santa Catalina Island, 14 of which hatched (Sharpe et al. 2004). A total of 47 chicks and 3 eggs (of which 2 hatched) were fostered into nests (Sharpe et al. 2004), and adult bald eagles successfully reared 40 of these 49 chicks. During this time, an additional 21 birds were also hacked onto the island (Sharpe et al. 2004). Because of the high DDE concentrations in the eggs, this active program of manipulation and augmentation is necessary to maintain bald eagles on Santa Catalina Island at this time.

Bald Eagle Territories on Santa Catalina Island

Nesting bald eagles have established five territories on Santa Catalina Island since 1984 (see Figure 3.4-3 in Section 3). A brief description of each territory is provided below.

  • The West End territory was established in 1991 and is located 0.5 kilometers (km) (0.3 miles) from the northwestern end of the island on a rock pinnacle approximately 75 meters (246 feet) above the water. The territory was initially occupied by a 10-year-old male and a 5-year old female, but a second female has assisted in breeding activities since 1992 (Sharpe et al. 2004). The nest has been used since 1991.
  • The Pinnacle Rock territory is located 4.3 km (2.7 miles) southwest of the city of Avalon. It was initially occupied in 1990 and the original pair, a 5-year old female and a 4-year old male, have continuously nested there since 1990 (Sharpe et al. 2004).
  • The Twin Rocks territory is located 5 km (3 miles) northwest of Avalon. The territory was first occupied in 1984 and contained active nests in 1985, 1987, and 1989. A new 4-year-old male joined the female of the original pair in 1995. The first eggs of the new pair were laid in 1997, but were abandoned after the egg switch. In 1998, the original female was replaced by a 12-year old female and this pair has nested in the territory every year to the present (Sharpe et al. 2004).
  • The Seal Rocks territory is located 4.5 km (2.8 miles) southeast of the city of Avalon. The original pair of this territory first nested in 1988. The female died on May 5, 1993, from DDE contaminant poisoning (Garcelon and Thomas 1997). In 1995, another adult female laid two infertile eggs. A new female and male began occupying the territory in 1997. In 1999, the pair laid one egg, but the nest was destroyed during a storm. The pair did not attempt to nest in 2000, but successfully fledged fostered chicks from 2001 to 2004 (Sharpe et al. 2004).
  • The Two Harbors territory is located 2 km (1.2 miles) southwest of the town of Two Harbors. This territory was first active in 2003, and was occupied by a pair of 5-year old birds. The male of this territory is an ACC-produced eagle that was fostered into the West End territory in 1998. The female hatched from an egg laid in the West End territory in 1998 and fostered into the Pinnacle Rock nest (Sharpe 2003).
Summary of Contaminant Data

Organochlorine contaminants, especially DDE, have been related to deleterious effects on bald eagle reproduction (Krantz et. al 1970, Grier 1982, Wiemeyer et al. 1984, 1993). Wiemeyer et al. (1993) reported that less than 3.6 micrograms per gram (µg/g) of DDE (wet weight) was found in eagle eggs where normal reproduction was occurring (mean 5-year production 1.0 fledgling per nest). When DDE levels in bald eagle eggs exceed 3.6 µg/g (wet weight), declines in productivity are expected (productivity was almost halved), with considerable reduction in productivity expected when eggs exceed 6.3 µg/g (wet weight) (mean 5-year production 0.27 fledgling per nest) (Wiemeyer et al. 1993).

In addition to DDE, other contaminants have been associated with reduced nest success (Wiemeyer et al. 1993, Nisbet 1989). Of particular concern are PCBs, which co-occur with DDTs in eagle eggs (Wiemeyer et al. 1993) and have adverse effects that translate into reduced number of fledglings produced per nest. The adverse effects associated with PCB exposure include embryo and chick mortality, edema, growth retardation, and deformities (Peakall 1994). Normal reproduction has been associated with eagle eggs containing less than 4.0 µg/g PCBs (Wiemeyer et al. 1984). In the analysis by Wiemeyer et al. (1993) of data on eagle eggs containing both DDTs and PCBs, less than 3.0 µg/g total PCBs (wet weight) was measured in eggs where mean 5-year productivity approached 1.0 fledgling per nest. Productivity was substantially reduced (0.61 fledgling per nest) in nests where eggs had more than 5.6 µg/g total PCBs (wet weight) (Wiemeyer et al. 1993).

Sprunt et al. (1973)reported that a minimum of 0.7 chicks per active nest is considered necessary to prevent a bald eagle population from declining. Kubiak and Best (1991) reported that 1.0 chick per nest is expected from a healthy eagle population. Similarly, the USFWS Pacific Bald Eagle Recovery Plan identifies the goal of 1.0 fledged young per pair with an average success rate per occupied site of not less than 65 percent over a 5-year period (USFWS 1986).

Contaminant Levels in Bald Eagle Eggs

Bald eagle eggs collected from Santa Catalina Island that failed to hatch have been monitored for DDE and PCB levels from 1989–2004 (Figures B-1 and B-2). Eagle eggs collected from the Pinnacle Rock and West End nests continue to show the highest DDE concentrations among the five different territories on the island. Unlike the other territories on the island, these nests have been occupied by the original female of that territory throughout the study period. Because these nests have been occupied by the same female over a period of 13 to14 years, continuous, long-term information on DDE concentrations in the eggs can be used to measure changes in contamination over time.